Computer application programs are widely used in business, industry and academic endeavors. There is a large and diverse segment of workers and consumers that must interface with these applications. The developers of many application programs are required to target a group of potential users having a broad range of skill levels. The program developer's choices in designing interfaces have a significant impact in the control of production operations. This vast area includes the printing trades, the production of parts, tools and dies, integrated circuit manufacturing and processing and chemical industry production as just a few examples. Because such production involves repetitive functions continuously performed over relatively long periods of time, the computerization of such operations takes advantage of the strengths of the computer. With the advance of computer control in production, the operator skill levels required for many operations has been reduced.
In production operations, high and continuous throughput is of prime importance. In display interfaces for controlling production operations, the operator at the interface is routinely provided with a sequence of error messages on the display screen. From time to time, such error messages are of sufficient significance for the operator to interrupt the operations and make changes to eliminate the error conditions. However, for the most part, error messages advise of conditions which either may be put off for subsequent action, require no action except for the operator to remain on alert for a potential or developing problem or may be beyond the skills and functions of the operator and thus may involve actions to be taken at a different operational level.
Most operations control systems have routines in place for shutting down operations when an error condition is so critical that it threatens injury to operators or damage to the operation equipment or products. As to all other error conditions, there is a need to alert the operator to the conditions, and to give the operator or the operations supervisor the opportunity to address the error condition immediately or to delay action until a future point in the operations.